The present invention relates to a readily disposable plastic molded product and a method for disposal of the same.
Thermosetting plastic molded products have wide applications including architectural, automobile, electric industrial and the like. These products include fiber-reinforced plastics incorporated with glass fiber, carbon fiber, organic fiber and the like, as well as particle-dispersed type plastic molded products incorporated with calcium carbonate, kaolin, talc, mica and the like.
In addition to these, aluminum hydroxide is added as a filler for giving a product a flame-retardant property.
Applications of these plastic molded products are roughly classified into two groups according to their structures, that is, laminated products and cast-molded products. The laminated products for architectural use include waved plates, flat plates, floorings, sidings or wall plates, bath tubs, lavatory tanks, water tanks, wash basins and the like; those for shipbuilding industry include yachts, boats, canoes, fishing boats, hydrofoils and the like; those for automobile industry include automobile bodies, air spoilers, camping trailers and the like; those for railway services include passenger cars, containers, berths, various tanks and the like; those for aero use include radar domes, propellers, ailerons, gliders and the like; those for mining and chemical industries include pipelines, tanks, reaction vessels and the like; those for electrical industry include various insulating plates, printed circuit boards, switch boards, casings, motors, transformers, video tape recorders, audio appliances and the like; those for other use include chairs, suit cases, helmets, surf boards, snow boards and the like. The cast-molded products in the architectural and civil engineering fields include artificial marble, tiles, doors, pipes, mortars, concrete and the like; those in the electric and communication fields include resins for sealing capacitors, coils, connecting terminals and the like; those for other use include buttons, ornaments, tablewares and the like.
Burning down or burying has hitherto been the common method for disposal of the thermosetting plastic molded products, and recycling such as thermal recycling has only partly been performed.
For recycling the molded products including FRP, BMC (bulk molding compound), SMC (sheet molding compound) and the like containing an inorganic substance, investigations are chiefly directed to a method of crushing the product and reusing the crushed powder as the filler by adding it to a virgin material up to about 20%, a method of chemically recycling the product by thermally decomposing it for recovering raw material, and a method of decomposing the product by microwave irradiation. Previously proposed specific measures may be exemplified as an equipment for producing a decomposed oil by crushing, melting and then thermally decomposing the molded product (Japanese Laid-Open Patent Publication Sho 62-32131), an equipment for converting the plastic wastes into oil (Japanese Laid-Open Patent Publication Sho 62-184034), a method for thermally decomposing wastes of glass fiber-reinforced thermosetting resins (Japanese Laid-Open Patent Publication Hei 4-100834), an equipment for disposal of FRP wastes (Japanese Laid-Open Patent Publication Hei 6-234879), and a method for thermally decomposing carbon fiber-reinforced plastics under a specific gas environment (Japanese Laid-Open Patent Publication Hei 6-99160). A crusher such as hammer mill and a heater are used in these methods.
The bulky plastic molded products occupy a large volume. This causes a problem of low efficient storing and transportation after their use. In order to solve the problem, mechanical crushing is usually performed. At present, the mechanical crushing consumes much energy and generates noise and the like. An advent of a technology for easily reducing the volume of the molded product is therefore eagerly required.
The thermosetting plastic molded products are frequently used as structural materials and may contain metals or other foreign matters if used for the molded motor, molded transformer or the like, or for sealing a semiconductor device. These molded components as the plastic molded products containing valuable objects such as metals and semiconductor tips are frequently buried just as they are at their disposal, and recycling of the valuable components and materials contained therein is ignored at present.
Further, crushing, thermal decomposition, decomposition by microwave irradiation and the like, which are methods for recycling FRP, SMC, BMC and the like, require a specifically designed large scale equipment and, in addition, all the methods consume much energy. Although various proposals are made on the thermal decomposition, in particular, a high temperature of not less than 300.degree. C. is required in any case.